Ashok Kumar Reddy

Clinical, microbiological profile and treatment outcome of ocular infections caused by Achromobacter xylosoxidans.

Purpose: To study the microbiological profile and outcome of ocular infections caused by Achromobacter xylosoxidans. Methods: Medical and microbiology records of patients with A. xylosoxidans ocular infections managed between May 2007 and December 2007 were reviewed. Results: The authors identified 10 patients whose eyes were infected by A. xylosoxidans during the study period. Of 10 patients, 8 had microbial keratitis, of whom 6 developed an infection after penetrating keratoplasty. The remaining 2 patients had endophthalmitis. The Gram-stained smear did not reveal any organism in 6 of 10 cases. In the 4 remaining cases, Gram-negative bacilli were reported. Out of 10 isolates, 9 were sensitive to ceftazidime, 7 to amikacin, 5 to ciprofloxacin, and 3 to ofloxacin, gatifloxacin, and chloramphenicol. Only one isolate was sensitive to moxifloxacin. Of the 6 patients with graft infection, 2 patients were lost to follow-up, infection was resolved in 3 patients, and the infection remained active in 1 patient. The two patients with endophthalmitis responded to antibacterial therapy and showed improved visual acuity. Infection was resolved in 2 patients with keratitis. Conclusion: Although A. xylosoxidans ocular infections are rare, one should retain a high index of clinical suspicion in patients who present with slowly progressive disease characterized by a localized infiltration and show Gram-negative bacilli on smear examination.

Post-operative endophthalmitis due to an unusual pathogen, Comamonas testosteroni

Here, we describe the first report of post-operative endophthalmitis due to Comamonas testosteroni in an elderly diabetic patient after complicated cataract surgery. The isolate was identified by using Mini API strips. The patient was successfully treated with intravitreal ceftazidime and oral ciprofloxacin.

Is microsporidial keratitis a seasonal infection in India

Microsporidia are emerging ocular pathogens. In this study, we describe the seasonal trends of microsporidial keratitis. The incidence of microsporidial keratitis is increasing in India, with a seasonal trend towards disease onset during the monsoon.

Speciation and susceptibility of Nocardia isolated from ocular infections

Twenty Nocardia spp. isolated from ocular infections were identified by 16S rRNA gene sequencing and susceptibility was determined using the E-test (AB Biodisk, Sweden). Species distribution among the 20 isolates was as follows: Nocardia levis (n = 7), Nocardia farcinica (n = 3), Nocardia abscessus (n = 2), Nocardia brasiliensis (n = 2), Nocardia amamiensis (n = 2), Nocardia puris (n = 1), Nocardia beijingensis (n = 1), Nocardia otitidiscaviarum (n = 1) and Nocardia thailandica (n = 1). All isolates were sensitive to amikacin. Eighteen (90%) isolates were sensitive to tobramycin, 11 (55%) to ciprofloxacin and gatifloxacin, and seven (35%) to azithromycin and clarithromycin. Molecular methods are useful for the identification and for the detection of Nocardia species that have not so far been reported in human infections.

Stenotrophomonas maltophilia endogenous endophthalmitis: clinical presentation, sensitivity spectrum and management.

Stenotrophomonas maltophilia is gaining importance as a community-acquired pathogen, after becoming firmly established as a nosocomial pathogen. Here we report a case of endogenous endophthalmitis due to S. maltophilia. Antibiotic-susceptibility testing of the isolate was performed by the Kirby-Bauer disc diffusion method. The organism was resistant to aminoglycosides, imipenem, ticarcillin and cotrimoxazole and was sensitive to ceftazidime and chloramphenicol. The patient was successfully treated with a sensitivity-based intravitreal antibiotic regimen.

Loop-mediated isothermal amplification assay for the diagnosis of retinitis caused by herpes simplex virus-1

Abstract A loop-mediated isothermal amplification (LAMP) assay was developed for the detection of herpes simplex virus 1 (HSV-1). The specificity of the assay was tested using DNA extracted from HSV-1-infected rabbit corneal epithelium cultures, HSV-2 grown on Vero cell line, cytomegalovirus (CMV) (AD-169), varicella zoster virus (VZV) (Oka-vaccine), adenovirus, Aspergillus flavus and Staphylococcus aureus. The specificity of LAMP was confirmed by bidirectional sequencing of the amplicons. The sensitivity of the LAMP assay was tested using different concentrations of HSV-1 DNA. To evaluate the application of the LAMP assay in clinical diagnosis, we tested vitreous samples from 20 patients with suspected viral retinitis using LAMP and real-time PCR for HSV-1. The LAMP primers amplified only HSV-1 DNA; no LAMP products were detected with the DNAs of HSV-2, CMV, VZV, adenovirus A. flavus and S. aureus. The sequences of the positive HSV-1 LAMP products perfectly (99–100%) matched the HSV-1 sequences deposited in the GenBank database. LAMP is as sensitive as real-time PCR, with the lowest detection limit being 10 copies/μL of HSV-1 DNA. Of the 20 patients with suspected viral retinitis, four tested positive for HSV-1 using real- time PCR and LAMP. A 100% concordance was observed across the two methods. The LAMP assay is a rapid, highly specific and sensitive method for the diagnosis of retinitis caused by HSV-1.

Risk factors and clinical outcomes of bacterial and fungal scleritis at a tertiary eye care hospital.

Purpose: The aim was to analyze demographics, risk factors, pathogenic organisms, and clinical outcome in cases with microbiologically proven bacterial or fungal scleritis. Materials and Methods: Retrospective review of all the medical records of patients with microbiologically proven infectious scleritis examined from March 2005 to December 2009 in the cornea services of L. V. Prasad Eye Institute, Hyderabad, India was done. Results: Forty-two eyes of 42 patients were included in this study. The mean age at presentation was 48.52 ΁ 14.10 years (range: 12-70). Surgery was the major risk factor seen in 24 eyes (58.5%). Scleral infection was noted after vitreoretinal surgery (with scleral buckle) in 15 eyes, cataract surgery in 3 eyes, pterygium surgery in 3 eyes, corneoscleral tear repair and scleral buckle surgery in 3 eyes. Sixteen eyes (39%) were on systemic or topical steroids at the time of presentation. History of injury was noted in 9 eyes (22%) and diabetes mellitus in 7 patients (17%). Associated keratitis was noted in 9 eyes (21.4%). The scleral abscess was unifocal in 33 eyes (78.5%), multifocal in 6 eyes (14.2%) and diffuse in 3 eyes (7.14%). The final follow-up ranged from 24 days to 37 months. The final visual acuity was better in 18 eyes (42.8%), stable in 13 (30.9%), and deteriorated in 7 eyes (16.6%). Recurrence was seen in 4 eyes (9.5%). Conclusions: Surgery is a major risk factor for infectious scleritis in our series. Fungus was the most common organism isolated. Thorough debridement and intensive use of medications have improved the outcome.

Endogenous endophthalmitis caused by Enterococcus casseliflavus

Herein, we report a case of endogenous endophthalmitis caused by Enterococcus casseliflavus. The organism was sensitive to gentamicin, vancomycin and chloramphenicol and resistant to cefazolin, ofloxacin, gatifloxacin and ciprofloxacin. The patient was successfully treated with vitrectomy and sensitivity-based intravitreal vancomycin.

PCR for the diagnosis and species identification of microsporidia in patients with keratitis

Corneal scrapings from 30 patients with microbial keratitis were subjected to microsporidial PCR. PCR was positive for microsporidia in ten of 30 patients. The species was identified as Vittaforma corneae by sequencing in all ten patients. The remaining 20 patients were negative for microsporidia and showed the growth of other organisms (Acanthamoeba, fungi or bacteria).

In Vitro Antibiotic Susceptibility of Rapidly Growing Nontuberculous Mycobacteria Isolated from Patients with Microbial Keratitis

Purpose: This study was undertaken to determine the antibiotic susceptibility and minimum inhibitory concentrations (MIC) of amikacin, tobramycin, ciprofloxacin, gatifloxacin, azithromycin, and clarithromycin against rapidly growing nontuberculous mycobacteria isolated from patients with keratitis. Methods: A total of 15 rapidly growing nontuberculous mycobacteria isolated from corneal scrapings of keratitis patients from January 1999 through December 2007 were subjected to antimicrobial susceptibility testing by the E-Test to amikacin, tobramycin, ciprofloxacin, gatifloxacin, azithromycin, and clarithromycin. Results: Out of 15 isolates, 13 were identified as Mycobacterium chelonae complex and 2 as Mycobacterium fortuitum complex. Based on minimum inhibitory concentration (MIC) cut off, all 15 (100%) isolates were sensitive to amikacin, azithromycin, and clarithromycin, 13 (86%) were sensitive to tobramycin, nine (60%) to gatifloxacin, and only 6 (40%) to ciprofloxacin. The MIC range was 0.25–4 µg/ml for amikacin, 0.5–1 µg/ml for azithromycin, 0.125–1 µg/ml for clarithromycin, 0.5–16 µg/ml for ciprofloxacin, and 0.25–16 µg/ml for tobramycin. MIC90 for amikacin was 2 µg/ml, azithromycin 1 µg/ml, clarithromycin 0.75 µg/ml, ciprofloxacin 8 µg/ml, gatifloxacin 8 µg/ml, and for tobramycin it was 4 µg/ml. Conclusions: All the isolates were sensitive to amikacin, azithromycin, and clarithromycin, but the MIC values of clarithromycin and azithromycin were lower than amikacin. Based on in vitro susceptibility results it appears that the topical amikacin in combination with oral clarithromycin or azithromycin is the best treatment option for rapidly growing nontuberculous mycobacterial keratitis.